I have developed what I believe is a cross-browser (latest versions of FF, IE, Opera anyway) Pure CSS Menu template (no JS). The menu works independently of the site css and is able to function within any Custom Block (assuming you make width correct...).
I would greatly appreciate any comments or issues you might encounter viewing this menu... it may be found at:
http://helpxoops.info
Once testing is complete, I will make the code available on HelpXOOPS to anyone who wants it.
...mark
may the road rise to meet your feet!
http://treemagic.org